In silo-like storage bins, bunkers and other forms of silos for bulk material, the stored bulk material frequently tends to compact and cause blockage of the delivery funnel, thereby preventing the movement of the bulk material during its discharge or cause complete interruption of its delivery. Frequently bridges of the bulk material are formed across opposing walls of the funnel to support the mass of the bulk material in the storage bin. Below the bridge the bulk material may be drained from the funnel while the bridge supports the remainder of the bulk material and prevents its emergence.
Various vibration devices have been developed with the object of loosening the bulk material in the funnel-shaped delivery area of the silo and to break up such bridges. One conventional construction provides a frane suspended elastically in the funnel-shaped delivery passage, the frame being provided with obliquely positioned wings as well as tapered downwardly turned guide elements. A jolting motor mounted on the frame generates the desired vibration. This construction has, however, the disadvantage that the vibrations generated by the jolting motor are applied only in a horizontal direction and are transmitted only to a limited degree, by means of the wings, to the bulk material located in the region of the funnel-shaped silo wall and has to be removed from time to time by hand. The vibrations which are propagated exclusively in a horizontal direction have been found to cause a compacting of the bulk material to some extent without effecting the desired loosening and flow promotion.